package gdut.jmxywz.util;
import java.awt.Color;   
import java.awt.Font;   
import java.awt.Graphics;   
import java.awt.image.BufferedImage;   
import java.io.ByteArrayInputStream;   
import java.io.ByteArrayOutputStream;   
import java.util.Random;   
import javax.imageio.ImageIO;   
import javax.imageio.stream.ImageOutputStream; 

public class RandomNumUtil {
	private ByteArrayInputStream image;//图像    
	private String str;//验证码    
	  
	private RandomNumUtil(){    
	init();//初始化属性    
	}    
	/*   
	* 取得RandomNumUtil实例   
	*/    
	public static RandomNumUtil Instance(){    
	return new RandomNumUtil();    
	}    
	/*   
	* 取得验证码图片   
	*/    
	public ByteArrayInputStream getImage(){    
	return this.image;    
	}    
	/*   
	* 取得图片的验证码   
	*/    
	public String getString(){    
	return this.str;    
	}    
	  
	private void init() {    
	// 在内存中创建图象    
	int width=60, height=20;    
	BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);    
	// 获取图形上下文    
	Graphics g = image.getGraphics();    
	// 生成随机类    
	Random random = new Random();    
	// 设定背景色    
	g.setColor(getRandColor(200,250));    
	g.fillRect(0, 0, width, height);    
	// 设定字体    
	g.setFont(new Font("Times New Roman",Font.PLAIN,18));    
	// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到    
	g.setColor(getRandColor(160,200));    
	for (int i=0;i<155;i++)    
	{    
	int x = random.nextInt(width);    
	int y = random.nextInt(height);    
	int xl = random.nextInt(12);    
	int yl = random.nextInt(12);    
	g.drawLine(x,y,x+xl,y+yl);    
	}    
	// 取随机产生的认证码(4位数字)    
	String sRand="";    
	for (int i=0;i<4;i++){    
	String rand=String.valueOf(random.nextInt(10));    
	sRand+=rand;    
	// 将认证码显示到图象中    
	g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));    
	// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成    
	g.drawString(rand,13*i+6,16);    
	}   
	//赋值验证码   
	this.str=sRand;    
	  
	//图象生效    
	g.dispose();    
	ByteArrayInputStream input=null;    
	ByteArrayOutputStream output = new ByteArrayOutputStream();    
	try{    
	ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);    
	ImageIO.write(image, "JPEG", imageOut);    
	imageOut.close();    
	input = new ByteArrayInputStream(output.toByteArray());    
	}catch(Exception e){    
	System.out.println("验证码图片产生出现错误："+e.toString());    
	}    
	  
	this.image=input;/* 赋值图像 */    
	}    
	/*   
	* 给定范围获得随机颜色   
	*/    
	private Color getRandColor(int fc,int bc){    
	Random random = new Random();    
	if(fc>255) fc=255;    
	if(bc>255) bc=255;    
	int r=fc+random.nextInt(bc-fc);    
	int g=fc+random.nextInt(bc-fc);    
	int b=fc+random.nextInt(bc-fc);    
	return new Color(r,g,b);    
	}   


}
